The evolution of animal genitalia – Menno Schilthuizen

The evolutionary tango
of animal genitalia. Can you guess what you’re looking at? If you answered “duck vagina,”
you’d be right. Although the bird’s outward appearance
may not strike you as especially odd, it uses this strange, intricate, cork-screw shaped contraption
to reproduce. We see similarly unbelievable genitalia
in insects, mammals, reptiles, fish, spiders, and even snails. Apparently, no organs evolve
faster and into more variable shapes than those involved in procreation. Superficially, it makes sense
because evolution works via reproduction. When an animal leaves more offspring,
its genes will spread. And since genitalia are an animal’s tools
for reproduction, any improvement there
will have immediate effect. And yet, what’s the point of having
such decorative nether regions? After all, the function
of genitalia seems simple. A penis deposits a bit of sperm and a vagina receives it
and delivers it to the egg. A pipette-like thingy on the male and a funnel-like gizmo on the female
should do just fine for any animal. And yet, that’s not what we see. The penis of a chicken flea, for example,
looks nothing like a pipette, more like an exploded grandfather clock. And the vagina of a featherwing beetle resembles something you’d find
in a Dr. Seuss book. Throughout the animal kingdom, genitalia are very complex things, much more complicated than seems
necessary for what they’re meant to do. That’s because genitalia do more than just
deposit and receive sperm. Many male animals also use the penis
as courtship device, like crane flies. In some South American species, males have a tiny washboard and scraper
on their penis, which produces a song that reverberates
throughout the female’s body when they mate. It’s thought that if female crane flies
enjoy this unusual serenade, they’ll allow the male
to father their offspring. This way, the genes of the most
musical penises spread, leading to rapid evolution
of insects’ phalluses. Similarly, some beetles have two little
drumsticks on either side of the penis. During mating, they’ll rub, slap, or tap
the female with these. And some hoofed mammals,
like rams and bulls, use a whip-like extension
on the penis’s left side to create a sensation during mating. But how can females really choose
between males if she can only assess them after mating? This is where the power
of female adaptation comes into play. In fact, insemination is different
to conception, and the female genitalia exploit
this distinction. For instance, in some dung flies, the vagina contains pockets
for separating sperm from different males depending on how appealing they were. Males using their penises for courtship and females controlling
their own sperm management are two reasons why genitalia evolve
into such complex shapes. But there are others because genitalia are also where
a sexual conflict is played out. A female’s interests are best served if
she fertilizes her eggs with the sperm of the best fathers and creates genetic variability amongst
her offspring. For a male, on the other hand,
this is bad news. For him, it would be best if a female
used his sperm to fertilize all of her eggs. So we see cycles of adaptation
in an evolutionary arms race to retain control. Black widow spiders
have a disposable penis tip that breaks off inside the vagina
blocking the attempts of his rivals, and bed bug males bypass a female’s
genitalia altogether using a syringe-like penis to inject
sperm cells directly into her belly. Not to be outdone, females have evolved
their own countermeasures. In some bed bug species, the females have evolved an entirely
new set of genitalia on their right hand flanks
where the males usually pierce them. That allows them to maintain
the power to filter out unwanted sperm with their genitalia. And duck vaginas are shaped
like a clockwise spiral so that when the male inflates his long,
counterclockwise coiled penis into her, and she disapproves, all she needs to do
is flex her vaginal muscles and the penis just flubs out. So, genitalia differs so much,
not just to fascinate us, but because in every species, they’re the result of
a furious evolutionary tango of sex that has been going on
for millions of years and will continue for millions
of years to come.


  1. J.C. Bonfils August 6, 2019 at 10:38 pm

    Okay. The infographics on this one were a bit much.

  2. Sonya Gilmore August 7, 2019 at 2:46 am

    So when I’m camping I might not be hearing a tiny waterfall or cricket 🤣

  3. Peng Fei Dong August 7, 2019 at 6:37 am

    Yes I spend my free time studying the genitalia of animals. I'm not crazy what are you talking about

  4. Peng Fei Dong August 7, 2019 at 6:46 am

    This video was probably demonetized so much

  5. sl1cky_n1cky August 7, 2019 at 11:58 am

    Ofc I'd be here at 5am.

  6. Mr.PicklesWorth Jr. August 7, 2019 at 3:04 pm

  7. Cuke Mom August 7, 2019 at 7:20 pm


  8. boister anto August 7, 2019 at 10:40 pm

    how is this video monetized

  9. End Creeper August 7, 2019 at 10:44 pm

    1:37 NO, CAT!!! DON'T TOUCH THAT!!!

  10. MaxtheOwl oof August 8, 2019 at 4:07 am

    Not to be weird or anything but this makes me feel weird about my ding dong…

  11. Miyuki Nguyễn August 9, 2019 at 2:52 am


  12. Bigby Wolf August 9, 2019 at 3:30 am

    That duck one though 😧

  13. AD AM August 9, 2019 at 5:56 am

    I was watching something about viruses. How did this happen?

  14. benis August 9, 2019 at 6:57 am

    why am I watching this at 2:56 am

  15. UG- LEE August 10, 2019 at 1:53 am

    0:50 BADLAND

  16. Golden Sperm August 10, 2019 at 4:02 am

    Is anyone ignoring that snake has two dicks.?

  17. Huey M. August 10, 2019 at 11:52 am

    I was eating 😅

  18. Solani Nomusa August 10, 2019 at 3:57 pm

    🤣 🤣 🤣 🤣 Ducks🤣🤣

  19. Seth Bell August 11, 2019 at 10:35 pm

    No one:

  20. franklyhanky August 13, 2019 at 12:24 am

    this video is not for the fame of heart XD

  21. Benjamin Abengona Rigor August 13, 2019 at 12:37 pm


  22. Tommy BRO August 14, 2019 at 12:41 am

    Furries be like…

  23. Scyce Fahim August 14, 2019 at 9:30 am


  24. jelly kitten August 14, 2019 at 8:06 pm

    Nature freaky

  25. Tamar H. August 15, 2019 at 4:36 am

    I was always confused by the "arms race" factoid about ducks. This helps explain it a lot better. Wild to think that there is competition for control going on at the biological level.

  26. Bir Azerbaycanli August 15, 2019 at 10:10 am

    2:38 ❌

  27. Marin Horațiu August 15, 2019 at 10:07 pm

    No one:
    Not a single soul:
    YouTube Reccomendations: time to learn about animal genitalia

  28. Ame San August 17, 2019 at 11:20 am

    2:41 nOsE bLeEdInG iNtEnSiFy

  29. Crimson_Pants August 18, 2019 at 4:17 am

    0:12 I about died

  30. Purple Spark August 18, 2019 at 11:50 am

    Can't believe we've studied the reproductive organs of bed bugs and yet don't have a way to terminate them

  31. Henry Herreman August 20, 2019 at 7:46 pm

    Now this is the quality content I subscribed for

  32. Mia phoenix August 21, 2019 at 2:44 am

    OK !

  33. Zain Hottson August 21, 2019 at 12:16 pm

    How educational.. ಥ‿ಥ

  34. Some Guy August 22, 2019 at 9:37 pm

    Time to sleep knowing that I might be hearing musics, penises when I take a stroll
    Also delete history

  35. PonyFucker August 24, 2019 at 12:10 pm

    I go masterb8 naw.

  36. Nishtha Sharma August 24, 2019 at 7:29 pm

    Female ducks have choices? I wish we humans could choose too 😐

  37. Alicat Gtz August 24, 2019 at 11:38 pm

    Time for genitalia fight club

  38. Ariel Tamang August 27, 2019 at 3:27 am

    i will give you my money if can circomcise a fly.. sorry dont know the spelling

  39. Onyx Blue August 31, 2019 at 4:33 pm

    ….I can't…look away

  40. Azure the Dragon king August 31, 2019 at 9:38 pm

    But do they get b o n e r s or all ways h a r d

  41. Violet Bui September 1, 2019 at 2:31 am

    ……why can't humans have genitalia like those!

  42. Sang Lê September 2, 2019 at 2:56 pm

    4:10 that is some solic hentai right there

  43. Wolf Dreamer September 4, 2019 at 12:38 pm

    I wonder how many times it took the narrator to read this without laughing.

  44. Pony Empires Unite September 5, 2019 at 2:08 am

    I've fallen down the rabbit hole.

  45. Sudipto Mandal September 5, 2019 at 5:50 am

    Pete Davidson❤❤❤

  46. QP Parks September 5, 2019 at 10:32 pm

    OK this will help in day to day life

  47. Cosmic Abby September 16, 2019 at 2:34 am

    I feel like I’m watching something… wrong…

  48. RolzZi E September 22, 2019 at 10:20 am

    Ok that’s fasanating………,,,,,……..

  49. WOO i DROO September 22, 2019 at 6:43 pm

    Why the heck would I guess that

  50. Call Me Yamato September 27, 2019 at 11:41 am

    What Did I Watch?

  51. Jeff Pomar September 28, 2019 at 2:58 pm

    I didn’t know that female beetles liked BDSM,,,

  52. Huy Tran September 29, 2019 at 1:14 pm

    What did you guys do to get this recommendation….because I don't know…

  53. Jastria Rahmat September 30, 2019 at 10:02 pm

    please make video about cloaca, and why gecko/lizard poop has white part on it. no youtube videos explain this yet

  54. Йончо !,.? October 6, 2019 at 5:53 am

    Me in 3am

  55. what the fuck is happening October 10, 2019 at 12:03 pm

    musical penises ohhh boiiii

  56. Gamer1 October 11, 2019 at 8:49 pm

    Lessons Worth Sharing.

  57. Mole Poopman October 12, 2019 at 12:49 pm

    What's that ? This two pink bulls mating in the savannah ??? 2:36 2:42

  58. Jaden Shelton October 13, 2019 at 5:23 pm


    Ted Ed: D U C K V A G I N A

  59. Zachary link October 16, 2019 at 12:38 am


  60. huanter and the ghost pokemon Gameing October 16, 2019 at 4:39 am


  61. Nararara Mammily October 17, 2019 at 1:33 pm

    How did I go from watching about Greek god, to food, to dogs and now animal’s private part?

  62. Adiano416 October 20, 2019 at 7:32 pm


  63. Ka Ching Andreas LUK October 25, 2019 at 10:40 am

    like an exploded grandfather clock —— BOOM !

  64. hoongz. zz October 25, 2019 at 4:09 pm

    Awesome so some hoofed mammals are into BDSM. Got it

  65. Rozalina Y October 25, 2019 at 9:59 pm

    How were you able to say this without laughing to death at any point and how were completely ok with this going on youtube?!

  66. Orca [ENG] October 26, 2019 at 9:41 am

    the despacito pp

  67. who else but zane? October 27, 2019 at 10:44 pm

    4:37 I hope this person got paid a lot to animate this

  68. nick stick October 30, 2019 at 4:17 am

    "the genes of the most musical penises"

  69. عاشق الكرة November 1, 2019 at 10:56 am

    📲*00212679620248* *whatapps*📲
    شـبـاب🙋‍♂️ لاحــظــت كــثــيــر كــومــنــتــات عــن تـكـبـيـر الـقـضـيـب وضــعــف الانــتــصــاب وسـرعـة الـقـذف
    ولا يــهــمــك😉 تــواصــلــو مـع الـدكـتـور👨‍⚕️ الــلــي نـصـحـنـي بـوصـفـة اسـتـعـمـلـتـهـا كــم أســبــوع وحــصــلــت عـلـى نــتــايــج مــذهــلــة🤩🥳
    الـلـي عـايـز الـدكـتـور👨‍⚕️ يــتــواصــل مـعـه الـواتـسـاب 00212679620248 *whatapps*📲

  70. Thumb Nail November 8, 2019 at 11:08 pm

    лучшее видео перед сном

  71. Ali Reza November 11, 2019 at 5:41 pm

    So, beetles are kinky

  72. Ashar November 11, 2019 at 6:11 pm

    I came here just to read comments. Who else came for the same ?

  73. Puia_Puipuia_Treee-P Chhakchhuak November 11, 2019 at 6:38 pm

    I was hoping that the male of the dancing bugs wud suddenly pierced the female, at the end of the video 😆😂

  74. cynthia van teylingen November 11, 2019 at 9:34 pm

    fasinating didnt know there were different genitals for other species. ill never walk through a meadow with insect sounds again without thinking what am i hearing exactly…..

  75. Ebi_Tempura November 11, 2019 at 10:59 pm

    … Why does this exsist?

  76. Initialhornet39 November 12, 2019 at 1:02 am

    -and will continue for millions of years to come

    I see what you did there

  77. Keith West November 13, 2019 at 1:23 am

    Fell asleep watching Ted ed and woke up watching this… WTF, Ted-ed

  78. Lucked November 13, 2019 at 1:56 am

    Why did click this

  79. Marissa Olanick November 13, 2019 at 3:07 am


  80. LongshotRecordsTV November 13, 2019 at 4:50 pm

    Cool beans

  81. FRISHR November 13, 2019 at 5:57 pm

    Furries have entered the chat

  82. FRISHR November 13, 2019 at 6:02 pm

    3:58 so that’s why Natasha Romanoff can’t have children.

  83. Yamaç Sungur November 13, 2019 at 7:33 pm

    Biz de zaman zaman benzer olaylarda bulunuyoruz

  84. SnowPeaShots9 November 20, 2019 at 6:12 am

    ive seen enough hentai to know where this is going…

  85. this snake in a suit November 23, 2019 at 10:59 am

    Was I just watching a vid about animals’ pps

  86. I hate Myself November 24, 2019 at 5:40 am

    What I got from this video:

    Clockwise duck Vaginas

  87. qwerty uiop November 24, 2019 at 9:50 am

    (laughs uncontrollably)

  88. Nikith Chhatbar November 24, 2019 at 6:46 pm

    Musical penises got me 😂😂

  89. jelenamat92 November 26, 2019 at 8:00 pm

    I actually did say 'a duck's vagina's'. Don't judge, you're watching this too.

  90. Prussian Productions November 27, 2019 at 4:46 pm

    Is nobody gonna talk about that spider cutting it's peepee thing?


  91. Droiz November 29, 2019 at 4:31 pm

    Everybody gangsta until penises start singing

  92. قهقاع !! December 1, 2019 at 2:13 pm

    سبحان الله، 👏

  93. Youngblood01 December 1, 2019 at 4:22 pm

    I’m just scrolling through YouTube and I see this and it peaked my interest

  94. Rene Umeh December 3, 2019 at 3:58 pm

    4:15 And she thought it was going to be a normal tinder date

  95. Brep Brep December 3, 2019 at 5:26 pm

    4:12 lol

  96. C Transcription December 5, 2019 at 9:09 pm

    . | /
    /. |.

    He see money 💴

  97. YanskiPlays Gaming December 7, 2019 at 3:03 am

    too much knowledge for today…

  98. Just A Frans Shipper December 7, 2019 at 11:00 am

    Rip the animators

  99. Glitchy Penny December 8, 2019 at 5:06 am

    Every boy is hurt at 4:50

  100. Joseph Stalin December 8, 2019 at 6:47 am

    Yo why tf was this in my recommended feed

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